Short-term synaptic plasticity in the deterministic Tsodyks-Markram model leads to unpredictable network dynamics
Short-term synaptic plasticity in the deterministic Tsodyks-Markram model leads to unpredictable network dynamics
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DOI：
10.1073/pnas.1316071110
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发表时间：
2013-10-08
影响因子：
11.1
通讯作者：
Sejnowski, Terrence J.
中科院分区：
文献类型：
--
作者：
Cortes, Jesus M.;Desroches, Mathieu;Sejnowski, Terrence J.
短期突触可塑性强烈影响皮层网络的神经动力学。用于短期突触可塑性的Tsodyks和Markram（TM）模型准确地解释了在不同类型的皮层突触处的广泛的生理反应。在这里，我们报告了一个通过Shilnikov同宿分岔，动态组织的TM模型中的一些响应的混沌行为的路线。特别是，这种同宿分岔的存在强烈地影响相空间中的轨迹的形状，并引起高度不规则的瞬态动力学;事实上，在Shilnikov同宿分岔附近，人口尖峰的数量及其精确的时间是不可预测的，并且对初始条件高度敏感。这样一个不规则的确定性动力学有其对应的随机/网络版本的TM模型：Shilnikov同宿分岔的存在产生复杂和不规则的尖峰模式和作为一种跳板，促进之间的转换下降状态和不稳定的周期轨道。（确定性）同宿分岔和随机效应之间的相互作用可能会引起一些复杂的动态观察神经系统。
Short-term synaptic plasticity strongly affects the neural dynamics of cortical networks. The Tsodyks and Markram (TM) model for short-term synaptic plasticity accurately accounts for a wide range of physiological responses at different types of cortical synapses. Here, we report a route to chaotic behavior via a Shilnikov homoclinic bifurcation that dynamically organizes some of the responses in the TM model. In particular, the presence of such a homoclinic bifurcation strongly affects the shape of the trajectories in the phase space and induces highly irregular transient dynamics; indeed, in the vicinity of the Shilnikov homoclinic bifurcation, the number of population spikes and their precise timing are unpredictable and highly sensitive to the initial conditions. Such an irregular deterministic dynamics has its counterpart in stochastic/network versions of the TM model: The existence of the Shilnikov homoclinic bifurcation generates complex and irregular spiking patterns and-acting as a sort of springboard-facilitates transitions between the down-state and unstable periodic orbits. The interplay between the (deterministic) homoclinic bifurcation and stochastic effects may give rise to some of the complex dynamics observed in neural systems.